NEW YORK, April 18, 2011 /PRNewswire/ -- When she marries Prince William, Kate Middleton will join the ranks of Princess Grace of Monaco and Queen Rania of Jordan as one of the most beautiful royals in history, according to the survey. (Logo: http://photos.prnewswire.com/prnh/20110418/LA84274LOGO ) Miss Middleton came in third in the poll, beating the late Diana, Princess of Wales who followed in fourth place. The exclusive online dating community, BeautifulPeople.com, provided a list of royals and told voters to choose who was the most beautiful.